We propose to systematically study the movement relations of cells throughout the RF in unrestrained cats: 1) Visual and polygraphic observations will be employed to determine the movement relations of RF units during spontaneous behaviors and during systematic behavioral manipulation. Units will be monitored during sleep-waking cycles to determine if any group of RF cells discharges selectively in REM sleep and could therefore have an "executive" role in its control. 2) Photographic techniques will be used to describe the temporal relationship between unit discharge and movement, and determine the precise topography of movements related to unit activity. 3) Spike triggered averages of EMG activity will be used to determine if the different classes of RF units are synaptically related to activit in recorded muscles and to investigate the pattern of unit-muscle relationships. These studies will lead to a better understanding of the functional roles of RF units. Systematic study and mapping of this brainstem motor control system should contribute to comprehension of its role in both normal behavior and in motor system pathology.